The Greeks had a word for it. For that collective, contagious fervour the Welsh call Hwyl. Enthusiasmos: literally, having the god within you. With its roots in the cult of Dionysus (other cultures had their own equivalent deities), this is something that our organised religion (and even our secular world) has disallowed and rendered taboo, particularly since the late Middle Ages (and not just thanks to Calvin and the Protestants...).
Apparently, one of the mysteries of this and similar cults is that in the state of collective ecstacy, when the individual loses all sense of their normal self, they also gain a glimpse of their immortal selves...as we do at gigs, at parties, on demonstrations and at state occasions
No wonder we distrust crowds, if they can reveal who we really are (and not what our minds tell us)...
Interesting thought for those of us who are advocating Enthusiasm Marketing with a passion...